The present invention relates to pumps generally, and more specifically to a liquid ring pump having a noise damping mechanism.
Liquid ring pumps typically comprise an open ended cup-shaped housing, an impeller rotatably supported in the housing adjacent a control disk and a cup-shaped member covering the open end of the housing. The impeller includes blades which in conjunction with surfaces thereabout form blade pockets or cells. A certain amount of liquid is trapped between adjacent blades in these pockets or cells. As the impeller turns, the liquid in a respective pocket Or space between adjacent blades moves in and out due to the impeller being eccentrically mounted in the pump housing. This creates, in effect, a liquid piston as the blades drive the captive ring of liquid around the inside of the casing. The cup-shaped cover member includes a conduit-like intake connection having an inlet opening and a conduit-like pressure connection having an outlet opening. These connections are associated with the cup-shaped cover member so that the inlet and outlet openings provide fluid communication between the intake and pressure connections, respectively, and the interior of the cup-shaped member facing the pump housing. The cup-shaped member further includes a partition wall which extends toward the cup-shaped housing and which is disposed between the inlet opening and outlet opening of the abovementioned connections. A control disk is arranged between the housing and the cup-shaped member so that the control disk and cup-shaped member together with the partition wall form a suction chamber in fluid communication with the intake conduit via the inlet opening and a surge chamber in fluid communication with the pressure conduit via the outlet opening. The control disk includes an inlet port and at least one outlet port formed therethrough, wherein the inlet port provides fluid communication between the suction chamber and at least one blade pocket and the outlet opening provides fluid communication between at least one blade pocket and the surge chamber. Accordingly, intake fluid, such as gas, is compressed within the pockets before the pockets line up with the outlet opening(s) prior to discharge.
Such a liquid ring pump is disclosed in European Patent No. 138,182. However, these liquid ring pumps present a problem in that they generate a very disturbing, roaring noise, especially at average intake pressures. This noise originates at the outlet opening(s) or orifice(s) formed in the control disk, through which the sealed-in and compressed gas is rhythmically exhausted. Then the noise is transmitted to the outside of the pump via the pressure conduit or external outlet connections. Thus, there is a need to develop a liquid ring pump which minimizes such noise.